drm/i915/ltphy: Compare only certain fields in state verify function

drm/i915/ltphy: Compare only certain fields in state verify function

Verify only the config[0,2] fields in the LT PHY state since these
are the only reliable values we can get back when we read the VDR
registers. The reason being that the state does not persist for other
VDR registers when power gating comes into picture.
Though not ideal this change does not hit us badly in perspective of how
we use the compare function to decide if fastset is required or if we
wrote the state correctly. VDR0_CONFIG and VDR1_CONFIG hold the values
that indicate the PLL operating mode and link rate which is usually
what we need to check if something has changed or not.

Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Link: https://patch.msgid.link/20260105055937.136522-2-suraj.kandpal@intel.com